1. Field of the Invention
The history of the art of ventilating foul air from toilet rooms goes back to the time when domestic and communal toilet facilities were first introduced. Venting of malodors directly from toilet bowls before they pervade in toilet rooms had been tackled in recent years by many in different ways and to different degrees of practicability, but without any noticeable commercial success. The purpose of the invention described herein is to provide a versatile and reliable self-ventilating toilet bowl that is economical to produce; simple to install, operate and maintain; and comfortable and hygienic to the user.
2. Description of the Related Art
Direct venting systems of toilet bowls which use filtration and/or deodorizing of malodor and then re-circulating the treated gases into toilet rooms have been taught by many in the prior art. Such systems although accepted by some are known to cause allergies and discomfort to many people. Additionally, operation of such systems rely on replaceable consumable components, which require continuous financing and maintenance, and are an additional burden on the environment.
Systems whereby malodor is exhausted directly from the toilet bowl to the outside either through a special duct directed to a ceiling extraction fan, or through a special hole in the toilet wall or ceiling have also been taught by many. Although such methods can be efficient from a functional point of view, the installation of ventilation ducts inside tidy toilet rooms is considered an unsightly proposition which most people would decline. Ventilation ducts in some cases can be obstructive to the user or to the cleaner. Drilling holes for ventilation ducts in toilet room walls and ceilings in addition to being aesthetically damaging to buildings is generally not allowed in rented property or in apartment buildings.
Systems whereby malodor is vented directly from the toilet bowl and exhausted into the drainage system has been described in many previous patents and studies, but none was found to cover the numerous and important details which, without being addressed meticulously, would place limitations on the practicability, function, reliability or hygiene of such systems. This probably explains the lack of commercial success of these inventions.
The two most common approaches for ventilating toilet bowls directly is whereby malodors are sucked by an electric fan from the toilet bowl through a flat intake nozzle placed between the toilet rim and the toilet seat, or through holes and a cavity incorporated into the toilet seat itself. Practical testing of suction methods of malodor directly from toilet bowls by the inventor have confirmed that the single intake nozzle solution (even with a 24VA electric fan) is sufficient to achieve the necessary venting of the toilet bowl without causing discomfort to the user from excessive noise or irritating air drafts caused by high power electric fans, while maintaining adequate and efficient ventilation of the toilet bowl.
Suction through holes and a cavity in the toilet seat itself will also provide the necessary ventilation of the toilet bowl, but at an unjustifiably higher cost to the consumer. Such systems also incur technical difficulties at the toilet seat hinges with the suction and/or exhaust pipes which are normally addressed by the deployment of flexible piping or hollowed hinges which double up as exhaust pipes. Since hinges are subject to continuous movement during use and cleaning, both such solutions can lead to early deterioration of components, which will require maintenance or replacement of parts to avoid inefficient performance. For example, see Japan Patents JP 2004-209192 and JP 2005-163512, and U.S. Pat. Nos. 6,772,449; 6,795,980 and 7,103,925.
The use of the single nozzle intake method is also strewn with shortcomings if attention to detail is not meticulously observed. If the nozzle is not fixed to the toilet assembly, the use of such a system will be limited to domestic toilets, and even there might still be subject to mishandling. For example, see Japan Patent No. JP 2006-144519 and U.S. Pat. Nos. 6,948,192 and 6,550,072.
U.S. Pat. No. 6,499,150 to Thompson discloses a configuration whereby an air intake nozzle, an electric ventilation fan and a secondary siphon are deployed below the toilet rim level, thus exposing all components to flooding by contaminated water should the toilet bowl get clogged during flushing of the toilet bowl, especially while the ventilating air fan is on. Additionally the configuration of the above-mentioned ventilation components is unduly complicated to manufacture and difficult to access for cleaning and maintenance purposes.
Published US patent application No. US 2002/0002735 of Moon discloses direct ventilation from the toilet bowl into the drainage system, but relies on an unduly complicated one-way air flapper deployed inside the air fan's exhaust duct to prevent the backflow of gases from the drains. Although a one-way air flapper on its own may prevent the backflow of gases into the air fan, many country codes consider such measures insufficient to block the ingress of contaminating germs, and insist upon specifying fluid traps (i.e., siphons) for that purpose.
Another example of such attempts to ventilate toilet bowls is disclosed in published US patent application No. US 2006/0096013 of Dang, which discloses “bubbling” of the discharged gases through the water contained in the siphon on the drain's side inside the toilet bowl. The water in the siphon is made to block the backflow of contaminating gases from the drain. However, in this arrangement, excessive sounds emanating from the bubbling action inside the toilet bowl during the ventilation process, and the possible long-term contamination of the exhaust hose with dangerous germs that may be carried into the air fan from traces of feces deposited downstream of the siphon, place limitations on the practicability or hygienic qualities of the system.